1. Field of the Invention
The present invention relates to a musical tone signal processing device which is suitable for use in the sound source synthesizing of the musical tone signals.
2. Prior Art
Generally, in order to synthesize and generate the musical tone signal or impart the sound effect to it, it is required to provide several kinds of operations, processes and much memory capacity. Actually, when configuring the device which generates the musical tone waveform or imparts the sound effect (e.g., reverberation effect) to the musical tone signal, it is required to give a careful consideration to the memory capacity and other control definitions such as the access time and number of bits of the data to be used.
When connecting the musical tone waveform processing device, using the 32-bit musical tone waveform data, to the memory having the predetermined memory capacity, the 32-bit data bus is generally used. In this case, however, by using the 8-bit data bus, it is possible to reduce the number of signal lines in the data bus as compared to the 32-bit data bus, with the result that the cost required for interconnecting the ICs can be reduced.
The above-mentioned theory can be easily proved in the typical example described below.
As an example, when interconnecting two memory systems which employ the same number "B", representing the bits of data, and the same data capacity "C=2.sup.n " but different sizes of the data buses, i.e., data buses of "B" bits and "B/a" bits, the first memory system, employing the B-bit data bus, requires the number of data 11nes at "B" and number of address lines at "n", while the second memory system, employing the B/a-bit data bus, requires the number of data 11nes at "B/a" and number of address lines at "n+log.sub.2 a".
For example, when "B" is set at "32" and "C" is set at 1MW=2.sup.20, we study about the following three cases wherein 32-bit, 16-bit and 8-bit data busses are used respectively. ##EQU1##
The conventional musical tone signal processing device employs the fixed number of bits in the data to be used. For this reason, it is necessary to provide the memory system of which data configuration must match with that of the conventional device, which may raise a drawback in that only the limited kind of memory system can be used. In other words, the customer cannot freely set the connecting specifications (such as the number of data lines to be used) between the processing portion and memory portion. In some cases, it is required to provide the high-price memory or large number of data lines, which may enlarge the size of the substrate board. This is a disadvantage when forming the system.